I individually bubble wrap each egg, burrito style, so each egg is totally enclosed. I pack up to 20 eggs in the small 7x7x5 USPS priority box, adding as much additional bubble wrap as needed so there is absolutely no room for those eggs to shift around inside the box. This box goes inside a larger 12x12x8 USPS priority box that is lined with egg cartons - currently an egg flat on the bottom, closed egg cartons on opposite sides, and half an egg carton on the other two opposite sides. The egg cartons keep the inner box perfectly centered and act as a cushion absorbing the energy and abuse and damage of shipping. I sometimes substitute air pillows for the half cartons to reduce weight.
"Sweating" should not be a problem if eggs are at room temperature when wrapped. Once eggs are packed, they are very well insulated. And they still wouldn't sweat because they're not exposed to humid air during the temperature change. IMO I don't think an egg will expire enough moisture through the eggshell during transit to cause "sweating". I have in the past rolled each egg in a paper towel strip cut to fit, but that was more for absorption in case of breakage than sweating. I have received no indication that adding the paper towels had an effect on the eggs either good or bad.
You ship beautifully. I took pictures when i opened the first box for future referance!
Since we are talking about shipping, i have a bad one for ya, i ordered some expensive serama eggs (50$ including shipping) and when i got them, it was a re used flat rate box, taped shut with blue and purple cheatah print duct tape. When i opened it up, i found a LOOSE egg carton, flopping around in the box. Opened the carton and dound not an ounce in any padding, other than half a paper towel pet egg, was used. I was mad! And not a 20$ shiping fee...